Vote centers were designed to make casting ballots easier and more convenient, but on Tuesday, they produced jangled nerves, technological gaffes and long lines across Colorado.

From urban Denver to suburban Douglas County to rural Routt County, there were long lines at vote centers.

Douglas County voters may have been hit the hardest, as some lined up more than four hours for a chance to cast a ballot.

Some left in frustration without voting and lashed out at election officials.

"They need to be held accountable for this," said Tanya Creighton, who tried to vote in the morning but faced a 1½-hour wait.

Creighton ended up waiting almost two hours at a voting center in the afternoon before she made it to a booth.

The most common complaint was the lack of computers needed to screen prospective voters.

One of the longest ballots in Colorado's history also kept voters pondering for up to 15 minutes each or longer, say election officials.

Douglas County spent $1.4 million on 300 new voting machines this year. Carole Murray, the county's election chief, said Wednesday that 500 were needed Tuesday.

The last vote was cast at 1:30 a.m. in Highlands Ranch.

The county will set up an advisory panel made up of residents, county officials, the secretary of state's office and representatives of the major parties to study ways to avoid a repeat in the 2008 presidential election.

"We need to do a better job as government," said County Commissioner Steve Boand. "Whether we need to add 200 machines or 300 more, I think we need some time to sort that out."

Poll officials in Routt County were not adequately trained to deal with the new electronic- voting machines and struggled to get the computers back online when the printers crashed, said Routt County Clerk Kay Weinland.

The length of the ballot and the 60 percent voter turnout also overwhelmed the available machines, Weinland said. He promised to solve the problem for the next election.

Denver officials today will discuss problems that led to two- to three- hour waits at the city's 55 vote centers, said at-large Councilman Doug Linkhart.

Among those problems were having only four or five computers at a vote center to check on hundreds of voter registrations. "It was a total fiasco," Linkhart said.

Tuesday afternoon, Denver election officials sent another 20 computers to centers in a move to ease congestion.

Larimer County, in 2003, was the first place in the country to replace traditional precincts with vote centers. The centers have been a huge success, said Clerk and Recorder Scott Doyle.

Voters can cast ballots at any vote center in the county, as long as they can prove they are a registered voter.

Doyle said each center has up to eight registration computers when the doors open and that more are brought in if there is a crush of voters.

"We try and move people through like a checkout line at Albertsons," Doyle said.